Spring mounted impact tool for breaking pavement



May 19, 1964 w. v. CORNETT SPRING MOUNTED IMPACT TOOL FOR BREAKING PAVEMENT Original Filed Nov. 18, 1960 Arrow/75.

United States Patent 3,133,730 SPRWG MQUNTED IMPACT TOUL FOR BREAKING PAVEMENT Walter V. Cornett, 2751 E. 11th St, Los Angeles, Calif. Continuation of application Ser. No. 70,329, Nov. 18, 1963. This application May 20, 1963, Ser. No. 281,836 13 Claims. (Cl. 262-14) The present invention is related to a device for breaking pavement, more specifically to a device which is selfmounted and self-propelled and which can be operated by a single individual to obtain excellent results. This application is a continuation of applicants copending application Ser. No. 70,329 filed November 18, 1960, now abandoned, and entitled Device for Breaking Pavement.

There are many situations wherein it is desirable and necessary to break up pavement or concrete so that construction or repair work may be carried out, for example, not infrequently sewer pipes and the like have to be laid beneath a street after the road has been paved. In such a case, a fairly narrow trench must be dug and the sewer pipe inserted therein. This necessitates a breaking up of a portion of the paved surface.

In other situations, it may be desirable to remove or break up pavement over a much wider area and even in some cases over the entire roadway itself. Occasionally there are settling problems which can be corrected only by removing the pavement and taking certain steps on the subsoil such as filling, draining and the like. Here again it is an essential prerequisite to the carrying out of this operation, that the pavement be first broken up and removed.

In the past, such operations were carried out by hand or by means of expensive equipment which had to be towed from place to place, or which was so highly specialized that it could be used for only one particular job.

It is, therefore, among the objects of this invention to provide a means for breaking concrete over either a long narrow area or a broad area, as is desired.

It is also among the objects of this invention to provide a pavement breaker which is self-propelled and easily operated by one man.

It is further among the objects of this invention to provide a pavement breaker which is of comparatively light construction and yet is capable of striking a very heavy blow.

It is still further among the objects of this invention to provide a combination of a pavement breaker and a compact, fast, mobile machine which can travel on the road at a speed as high as 50 to 55 miles an hour, and which also is capable of moving as slow as 14 feet per minute when in operation to provide substantially con tinuous breaking.

It is still further among the objects of this invention to provide a pavement breaker which is also capable of tamping backfill soil.

The present invention operates on a principle wherein a Whipping action is imparted to a free moving spring arm which is supported only at one end and the hammer or breaking tool, having a relatively heavy Weight, can exert a sudden and heavy blow on the concrete which blow is a maximum at the point of impact. The amount of power or force exerted is readily controllable by the operator of the machine. In addition, the machine is readily maneuverable by reason of a turntable mounting of the spring arm and the linkage through which the force is exerted to operate the arm.

In practicing this invention there is provided a chassis with a turntable rotatably mounted thereon. A yoke is affixed to the turntable and a resilient hammer arm is pivotally mounted on the yoke.

3,133,730 Patented May 19, 1964 The device is actuated by hydraulic pressure fed to two hydraulic cylinders. The first hydraulic cylinder carries Within it a ram, one end of which is linked to the turn table preferably near the periphery thereof. The intro duction of fiuid under hydraulic pressure alternately to one side or the other of the ram, causes reciprocating rotation of the turntable and the yoke and hammer arm connected thereto. Since the turntable rotates about a vertical axis, this permits the hammer arm to swing from side to side.

The hammer arm itself being pivotally mounted on the yoke which in turn is mounted on the turntable, is adapted for reciprocation in a vertical plane. The arm is actuated by a second hydraulic cylinder with a second ram therein. The second ram is connected to the arm at a point spaced apart from the pivot of the arm. Thus in a manner analogous to the actuation of the turntable, the introduction of hydraulic fluid on either side of the ram causes the arm to reciprocate in a vertical plane.

Thus by a combination of movement of the first and second hydraulic rams, the hammer arm can be caused to strike the pavement or surface to be broken or tamped at any point along the are represented by the position of the hammer head throughout the permitted rotational movement of the turntable. By adjustment of the forward or backward movement of the chassis, the length of the area to be covered can be controlled.

The hammer arm itself is of resilient material and in the preferred embodiment comprises a pair of leaf springs bound together at regular intervals.

The foregoing spring arrangement permits a substantial amount of flexing (particularly at the upper end of the vertical reciprocation) and thus gives increased force when the hammer contacts the surface at the lower end of vertical reciprocation.

For best control, the two hydraulic cylinders should be independent of each other so that the device achieves greater flexibility of operation.

In the accompanying drawings constituting a part hereof, in which like reference characters indicate like parts.

FIG. 1 is a plan view of the impact device;

FIG. 2 is an elevational view of the impact device with non-essential parts broken away for clarity; and

FIG. 3 is a schematic diagram of the hydraulic fluid system.

The impact device 1 comprises chassis 2 mounted on wheels 3. The operator is seated on chair 5 in front of controls 4. Hammer arm 6 composed of leaf springs 7 and 8 is pivoted on yoke 13 at pivot 14. Yoke 13 is mounted on turntable 36 which is rotatably mounted on chassis 2 at 12.

Hammer arm 6 carries hammer head 9 at its extremity furthest from chassis 2. Mounted on hammer head 9 is breaker 10.

First hydraulic cylinder 17 pivotally mounted on the chassis has its ram pivotally connected through link 18 to car 19 on the periphery of turntable 36. Second hydraulic cylinder 16 is pivoted at one end to post 16 and has its ram pivotally connected to link 15. Link 15 is affixed to arm 6 and also is pivoted at 14 to the chassis. Thus movement of the ram in cylinder 16 causes link 15 to pivot around 14 and impart vertical motion to arm 6. Hydraulic fluid is contained in tank 21 and the pressure is maintained by pump 22 driven by pump motor 23. The entire device is propelled by engine 20.

In operation, the operator adjusts the horizontal position of the hammer head 9 through horizontal control valve 37. By introducing hydraulic fluid under pressure to one side or the other of the ram in cylinder 17, turntable 36 through link 18 and ear 19 is caused to rotate accordingly.

After the hammer head 9 is in position, the blow is struck by the actuation of vertical control valve 29. Hydraulic pressure is introduced thereby into the upper end of cylinder 16, causing the hammer arm 6 and hammer head 9 to assume the position as at 25 in FIG. 2. The flexibility of hammer arm 6 gives added force due to the resilience of the aforementioned hammer arm. The hydraulic fluid is then introduced under pressure into the lower end of cylinder 16, causing the arm 6 to pivot about 14, with the added force of the resilience resulting from the assumption of position 25, thereby causing the hammer head 9 to strike the pavement as shown at 24 in FIG. 2.

The hydraulic system works as follows. The fluid is stored in tank 21 and when needed is drawn through tube 26 by pump 22 driven by motor 23. From pump 22 it passes under pressure through pipe 27 to T-joint 28. Since from this point on the operation of valves 29 and 37 are the same, only one will be described. The fluid is then conducted from T-joint 28 through pressure tube 30 to the in-take of valve 29. Then depending upon the desires of the operator, it is conducted from valve 29 either through pipe 31 to the upper portion of cylinder 16 or through pipe 32 to the lower portion of cylinder 16. At the same time, valve 29 connects pressure tube 30 with one of pipes 31 or 32, which connects the other of these pipes to outlet 33 of valve 29. Outlet 33 returns the fluid through T-joint 34 and return line 35 to tank 21.

As indicated herein, the operation of valve 37 to operate cylinder 17 is analogous to the foregoing description.

Although only one specific embodiment of this invention has been specifically described, it is nevertheless to be broadly construed and not to be limited except by the character of the claims appended hereto.

What is claimed is:

1. An impact device comprising, a vehicle chassis, a turntable mounted on said chassis, a pair of spaced arms defining a yoke projecting forwardly beyond the chassis, said yoke mounted on said turntable, an ear projecting radially from the turntable, a fluid operated cylinder having a piston rod extending from it and attached to the ear to secure rotative positioning of the turntable, a pair of lengthy leaf springs arranged in side-by-side relationship pivoted at one end in the yoke, a striking tool arranged at the free ends of the springs and connecting said ends together, an arm projecting from the springs adjacent to their point of pivotalconnection to the yoke, a supporting post on said turntable rising above the pivoted ends of the springs, a vertically-disposed fluid cylinder pivotally attached at one end to the post and extending vertically downwardly therefrom and having a piston rod pivotally attached to the arm.

2. An impact device comprising, a vehicle chassis, a turntable mounted on said chassis, a leaf spring constituting a hammer-supporting means pivoted at one end to a forward portion of the turntable and being otherwise free from attachment to said chassis, a hammer rigidly attached to the free end of the leaf spring, a post mounted on and projecting upwardly from said turntable adjacent the pivoted end of said spring, a fluid cylinder pivotally mounted on said post and having a piston rod pivotally connected to said leaf spring, thereby to impart an upand-down force to the leaf spring to thereby swing the leaf spring up and down. on its pivot and apply a whipping action to the spring at its opposite limits of swing.

3. An impact device having a chassis, an arm extending therefrom, a tool rigidly secured on the free end of said arm, the other end of said arm being mounted on said chassis for oscillating movement of said arm and tool in a substantially vertical plane, said arm comprising a plurality of superposed spring plates, the number of plates at said other end being greater than the number at said free end of said arm, said arm being composed of two sets of said spring plates in spaced side by side relation, and having means at both ends for connecting said sets together.

4. An impact device comprising a chassis, a turntable on a pivot mounted on the front end of said chassis, a yoke on said turntable extending forwardly, a horizontal pivot on the front of said yoke, a hammer arm extending forwardly, said arm being springy, the rear of said arm mounted on said horizontal pivot, a tool rigidly secured at the front of said arm, a post on said turntable, a hydraulic cylinder pivoted on said post, a piston and piston rod operating in said cylinder, a link fixed to said arm and pivoted to said rod and adapted to move said arm in a vertical direction in an are.

5. An impact device according to claim 4 characterized in that said arm consists of a plurality of superposed leaf springs.

6. An impact device according to claim 4 characterized in that said arm consists of a plurality of superposed leaf springs increasing in number from front to rear.

7. An impact device according to claim 4 characterized in that said yoke consists of a pair of spaced bars between which said arm is pivoted.

8. An impact device according to claim 4 characterized in that said arm has two substantially parallel sets of superposed leaf springs terminating in said yoke and tool.

9. An impact device according to claim 4 characterized in that said cylinder is vertical and said link is adapted to oscillate in a vertical plane.

10. An impact device according to claim 4 characterized in that a seat for an operator is mounted on said chassis, and a control for said turntable and arm in front of said seat is mounted on said chassis.

11. An impact device according to claim 4 characterized in that said link is attached to the top of said arm and said pivot passes through said link.

12. An impact device according to claim 4 characterized in that a second hydraulic cylinder in horizontal position is pivotally mounted on said chassis and a piston rod in said second cylinder is pivotally linked to said turntable at a point remote from the pivot of said turntable.

13. An impact device comprising an elongated leaf spring having a base, said spring tapering from its base to the free end thereof, a chassis, a mount for said base on said chassis, a horizontal pivot on said mount, the spring base being pivoted thereon, means on said mount connected to said base for imparting arcuate movement to said spring, said pivot being the sole support for said spring, an impact tool fixed on said free end of said spring and directly mounted on said end, whereby by said arcuate movement a whipping action is imparted to said tool, said spring embodying a pair of spaced tapered leaf springs side by side and connected together at said base and at said free end, whereby lateral twisting of said tool is practically prevented.

References Cited in the file of this patent UNITED STATES PATENTS 1,841,802 Gettelman Jan. 19, 1932 2,335,172 Cornett Nov. 23, 1943 2,788,201 Lindgren et a1 Apr. 9, 1957 FOREIGN PATENTS 164,576 Austria H Nov. 25, 1949 

2. AN IMPACT DEVICE COMPRISING, A VEHICLE CHASSIS, A TURNTABLE MOUNTED ON SAID CHASSIS, A LEAF SPRING CONSTITUTING A HAMMER-SUPPORTING MEANS PIVOTED AT ONE END TO A FORWARD PORTION OF THE TURNTABLE AND BEING OTHERWISE FREE FROM ATTACHMENT TO SAID CHASSIS, A HAMMER RIGIDLY ATTACHED TO THE FREE END OF THE LEAF SPRING, A POST MOUNTED ON AND PROJECTING UPWARDLY FROM SAID TURNTABLE ADJACENT THE PIVOTED END OF SAID SPRING, A FLUID CYLINDER PIVOTALLY MOUNTED ON SAID POST AND HAVING A PISTON ROD PIVOTALLY CONNECTED TO SAID LEAF SPRING, THEREBY TO IMPART AN UPAND-DOWN FORCE TO THE LEAF SPRING TO THEREBY SWING THE LEAF SPRING UP AND DOWN ON ITS PIVOT AND APPLY A WHIPPING ACTION TO THE SPRING AT ITS OPPOSITE LIMITS OF SWING. 